Hämodynamische Effekte von Noradrenalin und Norfenefrin unter NO-Synthase-Inhibition im endotoxämischen Schaf

Um die Wirkungen zwischen dem a-agonistisch wirkenden Katecholaminen Noradrenalin (NA) und Norfenefrin (NF) in Kombination mit dem unselektiven NOSI L-NAME zu untersuchen, wurden Schafe in einem Modell der hyperdynamen Sepsis hämodynamisch untersucht. Den gesunden und endotoxämischen Tieren wurden entweder NA oder NF intravenös ohne und mit L-NAME appliziert. Des Weiteren wurde in gesunden Tieren der Einfluss des a2-Antagonisten Yohimbin auf die hämodynamischen Effekte von NA und L-NAME bzw. der Einfluss des zentralen a2-Agonisten Clonidin auf L-NAME untersucht. In gesunden und in septischen Tieren war der Anstieg von MAD und SVRI unter L-NAME und NA-Gabe stärker ausgeprägt als unter NF. Yohimbin schwächte die Wirkung von NA unter NOSI stark ab. Clonidin bewirkte unter NOSI einen paradoxen Anstieg von MAD und SVRI. L-NAME scheint einen a2-vermittelten, potenzierenden Effekt auf die vasopressorische Aktivität von NA, nicht aber auf NF zu besitzen

ASi-Sii defect model of light-induced degradation (LID) in silicon: a discussion and review

The ASi-Sii defect model as one possible explanation for light-induced degradation (LID) in typically boron-doped silicon solar cells, detectors, and related systems is discussed and reviewed. Starting from the basic experiments which led to the ASi-Sii defect model, the ASi-Sii defect model (A: boron, or indium) is explained and contrasted to the assumption of a fast-diffusing so-called “boron interstitial.” An LID cycle of illumination and annealing is discussed within the conceptual frame of the ASi-Sii defect model. The dependence of the LID defect density on the interstitial oxygen concentration is explained within the ASi-Sii defect picture. By comparison of electron paramagnetic resonance data and minority carrier lifetime data related to the assumed fast diffusion of the “boron interstitial” and the annihilation of the fast LID component, respectively, the characteristic EPR signal Si-G28 in boron-doped silicon is related to a specific ASi-Sii defect state. Several other LID-related experiments are found to be consistent with an interpretation by an ASi-Sii defect

Supersymmetric ZN×ZM orientifolds in 4D with D-branes at angles.

We construct orientifolds of type IIA string theory. The theory is compactified on a T6/ZN×ZM orbifold. In addition worldsheet parity in combination with a reflection of three compact directions is modded out. Tadpole cancellation requires to add D-6-branes at angles. The resulting four dimensional theories are N=1 supersymmetric and non-chiral

Development of low-gain avalanche detectors in the frame of the acceptor removal phenomenon

Low-gain avalanche detectors (LGAD) suffer from an acceptor removal phenomenon due to irradiation. This acceptor removal phenomenon is investigated in boron, gallium, and indium implanted samples by 4-point-probe (4pp) measurements, low-temperature photoluminescence spectroscopy (LTPL), and secondary ion mass spectrometry (SIMS) before and after irradiation with electrons and protons. Different co-implantation species are evaluated with respect to their ability to reduce the acceptor removal phenomenon. In case of boron, the beneficial effect is found to be most pronounced for the low-dose fluorine and high-dose nitrogen co-implantation. In case of gallium, the low-dose implantations of carbon and oxygen are found to be beneficial. For indium, the different co-implantation species have no beneficial effect. SIMS boron concentration depth profiles measured before and after irradiation show no indication of a fast movement of boron at room temperature. Hence, the discussed BSi-Sii-defect explanation approach of the acceptor removal phenomenon seems to be more likely than the other discussed Bi-Oi-defect explanation approach

Effect of inelastic ion collisions on low-gain avalanche detectors explained by an A_Si-Si_i-defect mode

The acceptor removal phenomenon (ARP), which hampers the functionality of low-gain avalanche detectors (LGAD), is discussed in frame of the A_Si-Si_i-defect model. The assumption of fast diffusion of interstitial silicon is shown to be superfluous for the explanation of the B_Si-Si_i-defect formation under irradiation, particular at very low temperatures. The experimentally observed properties of the ARP are explained by the donor properties of the B_Si-Si_i-defect in its ground state. Additionally, low temperature photoluminescence spectra are reported for quenched boron doped silicon showing so far unidentified PL lines, which change due to well-known light-induced degradation (LID) treatments

Anisotropic surface reaction limited phase transformation dynamics in LiFePO4

A general continuum theory is developed for ion intercalation dynamics in a single crystal of a rechargeable battery cathode. It is based on an existing phase-field formulation of the bulk free energy and incorporates two crucial effects: (i) anisotropic ionic mobility in the crystal and (ii) surface reactions governing the flux of ions across the electrode/electrolyte interface, depending on the local free energy difference. Although the phase boundary can form a classical diffusive "shrinking core" when the dynamics is bulk-transport-limited, the theory also predicts a new regime of surface-reaction-limited (SRL) dynamics, where the phase boundary extends from surface to surface along planes of fast ionic diffusion, consistent with recent experiments on LiFePO4. In the SRL regime, the theory produces a fundamentally new equation for phase transformation dynamics, which admits traveling-wave solutions. Rather than forming a shrinking core of untransformed material, the phase boundary advances by filling (or emptying) successive channels of fast diffusion in the crystal. By considering the random nucleation of SRL phase-transformation waves, the theory predicts a very different picture of charge/discharge dynamics from the classical diffusion-limited model, which could affect the interpretation of experimental data for LiFePO4.Comment: 15 pages, 10 figure